Cleanup after non-Linux code removal.

Conditions such as defined(LINUX) are always true now,
defined(FREEBSD) etc are always false.
When if directive has them as subexpressions, it can be simplified.
Another trivial changes here are fixes for directive indentation.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/ipc.c b/ipc.c
index 963537e..d8757c1 100644
--- a/ipc.c
+++ b/ipc.c
@@ -62,7 +62,7 @@
 #define SEM_INFO 19
 #endif
 
-#if defined LINUX && !defined IPC_64
+#if !defined IPC_64
 # define IPC_64 0x100
 #endif
 
@@ -421,11 +421,11 @@
 		if (syserror(tcp))
 			return 0;
 /* HPPA does not use an IPC multiplexer on Linux.  */
-#if defined(LINUX) && !defined(HPPA)
+#if !defined(HPPA)
 		if (umove(tcp, tcp->u_arg[2], &raddr) < 0)
 			return RVAL_NONE;
 		tcp->u_rval = raddr;
-#endif /* LINUX */
+#endif
 		return RVAL_HEX;
 	}
 	return 0;